🎹 Automatic Bass Chord Compendium


The Automatic Bass Chord keyboard line came in three models: PS-10, PS-20, and PS-30. Each an extension of the previous.

The PS-10 has 44 keys, while the other models have 49.


Orchestral Section

The orchestral sound bank provides the primary method of performing on any of the PS models. Sounds include:

(* - not present on PS-10)

A sustain button is also found in this bank, which adds a long tail to the end of a played note. When this mode is disabled, sound stops immediately when a key is released. (This mode is always enabled for the Vibraphone sound)

Auto Rhythm

A bank of rhythmic patterns allows you to play along with a percussive loop in various styles:

(* - Not present on PS-10, † - only present on PS-10)

To start the rhythm, all models support a “synchro start” mode. When this button is pressed, the rhythm starts as soon as one of the bass-section keys are played. The tempo of the pattern is controlled with a slider, and indicated by an LED above the section.

The PS-20 and PS-30 both have a second start button that will start the pattern immediately. They also feature a button labeled “8 Bar Variation”, which inserts a variation of the pattern every 8 bars after the button was pressed.

This section has its own volume slider as well, which effects the percussion portion of each pattern.

Auto Bass Chord

The titular feature of these keyboards is its automatic bass chord section. This section provides an instrumental accompaniment to the any currently playing rhythm, as well as a constant chord when no rhythm is playing.

To disable, select “Normal” on the PS-20 and PS-30, or toggle off Single Finger Mode on the PS-10

When enabled, keys below F#2 control the bass chord being played. There are two modes

Single Finger Chord

The simplest mode, and available on all models, Single Finger Chord mode allows the player to play a chord with a single finger, or up to 3 for chord variations

A single note played results in a major chord with that root.

A minor chord can be played by adding a lower black key. The highest note will be the root.

A 7th chord is played similarly by adding a lower white key.

Finally a minor 7th chord can be played by adding a lower black and white key.

Fingered Chord

(Not present on the PS-10)

This mode allows the direct input of chords within the bass keys. Just play the chord!

Other options

On the PS-20 and PS-30, there are two additional buttons.

Memory latches played chords, until another is played, or the button is toggled off.

Multi Bass Switches to an alternative bass pattern for the selected rhythm.

Auto Arpeggio

(Not present on the PS-10)

When the rhythm and auto bass sections are playing, an arpeggio can be added with the arpeggio volume slider. Moving the volume to MIN disables the arpeggio.

The variation button switches to an alternate arpeggio pattern.

Solo Section

(PS-30 only)